The Rev. Al Sharpton, center, with Jeffrey Campaign, left, a gay rights organizer, and the NAACP President Benjamin Todd Jealous, at a news conference by a gay rights organization to announce a march to protest the stop-and-frisk practice by New York police, in New York, June 5, 2012. Since the relationship between gay rights organizations and the country's major civil rights organizations reached something of a crisis with the passage of Proposition 8, California's ballot initiative against same-sex marriage, in 2008, leaders in both movements have made a concerted effort to bring their groups closer together. (Christopher T. Gregory/The New York Times)

For years, gay rights organizations and major civil rights organizations viewed each other warily. African American leaders often saw the gay rights groups as insensitive to racial concerns, and some resented the movement's use of civil rights language to make the case for same-sex marriage. Advocates for gay rights, in turn, sometimes blamed socially conservative African Americans for their defeat in crucial electoral battles.

But since the relationship reached something of a crisis with the passage of Proposition 8, California's ballot initiative against same-sex marriage, in 2008, leaders in both movements have made an effort to bring their groups closer together.

Now, a series of conversations among leaders in the gay, black and Latino communities have borne significant fruit: On May 19, the board of the NAACP formally voted to endorse same-sex marriage.

And then, Tuesday, representatives of several national gay rights organizations gathered at New York City's Stonewall Inn, often described as the birthplace of their movement, to announce that they would march to protest the New York Police Department's stop-and-frisk practice, under which the police each year have been stopping hundreds of thousands of New Yorkers, most of them black or Latino, in an effort to prevent crime.

Some of the gay rights leaders specifically cited support from the NAACP for same-sex marriage as a reason they decided to oppose the stop-and-frisk policy.

"We need to find ways to strengthen our alliances and really strengthen our commitment to one another," said Jeffrey Campagna, a national gay rights organizer who is coordinating the involvement of gay rights groups in the June 17 march against the stop-and-frisk practice.

Julian Bond, a former chairman of the NAACP and a founder of the Student Nonviolent Coordinating Committee, said he saw the association's support for same-sex marriage as a way to acknowledge the contributions of gay rights advocates, most closeted at the time, in the civil rights movement.

"I knew these people, whom I just assumed to be gay, and I knew what they were doing on my behalf," he said. "I was grateful for it, and when the chance came, I wanted to pay them back."

The same-sex marriage and stop-and-frisk issues are only the most visible signs of closer collaboration.

Around the country, gay rights groups have joined minority advocacy organizations in political battles on behalf of voting rights and affirmative action. And in California, Oregon and Colorado, gay rights organizations have formed partnerships with immigrants rights groups to fight aggressive immigration laws.

And even before the national board of the NAACP voted to support same-sex marriage, that organization and other civil rights groups got involved in marriage battles on the state level. In North Carolina, the NAACP paid for radio and print advertisements, direct mail and robocalls urging black voters to oppose an amendment banning same-sex marriage; the amendment passed in May. In Maryland, where the state Legislature voted to legalize same-sex marriage in February, the Rev. Al Sharpton of the National Action Network and Wade Henderson of the Leadership Conference on Civil and Human Rights were prominent supporters.

"You must be for the civil rights of everyone or you're not for the civil rights of anyone," Sharpton said last week.

One indication of the new rapport: Chad Griffin, who is taking over Monday as president of the Human Rights Campaign, the nation's leading gay rights group, plans to have lunch on one of his first days in Washington with the president of the NAACP, Benjamin Todd Jealous.

The communication between the two communities has picked up since the disclosure in March of a memorandum by the National Organization for Marriage, the leading group opposing same-sex marriage in the country, that described a goal to "drive a wedge between gays and blacks" over same-sex marriage.